Water absorbable rigid urethane foam compositions

ABSTRACT

WATER ABSORBABLE RIGID POLYETHER POLYURETHANE FOAM COMPOSITIONS USEFUL AS FLORAL FOAMS, BAFFLES AND FILTERS ARE PREPARED BY SUBJECTING TO FOAMING CONDITIONS A COMPOSITION COMPRISING (A) AN AMINE INITIATED, HIGHLY BRANCHED POLYETHER POLYOL, (B) A HIGHLY BRANCHED HYDROXYL INITIATED POLYETHER POLYOL, (C) A HIGHLY BRANCHED HYDROXYL INITIATED POLYETHER POLYOL AND (D) A POLYMETHYLENE POLYPHENYL ISOCYANATE.

United States Patent 3,746,666 WATER ABSORBABLE RIGID URETHANE FOAMCOMPOSITIONS Gerald Wayne Neal and Llewellyn Delphin Booth, LakeJackson, Tex., assigmors to The Dow Chemical Company, Midland, Mich. NoDrawing. Filed Aug. 2, 1971, Ser. No. 168,366 Int. Cl. C08g 22/14, 22/46US. Cl. 260-25 AD 4 Claims ABSTRACT OF THE DISCLOSURE Water absorbablerigid polyether polyurethane foam compositions useful as floral foams,bafiles and filters are prepared by subjecting to foaming conditions acomposition comprising (A) an amine initiated, highly branched polyetherpolyol, (B) a highly branched hydroxyl initiated polyether polyol, (C) alightly branched hydroxyl initiated polyether polyol and (D) apolymethylene polyphenyl isocyanate.

This invention relates to water absorbable rigid polyurethane foams andmore particularly concerns rigid polyether urethane foams which arecharacterized as having the ability to absorb 70% by volume of waterwhen immersed therein for 3 minutes, to foamable compositions which whensubjected to foaming conditions produce such foams and a process fortheir production.

The rigid polyether polyurethane foams of the present invention areprepared by intimately admixing in the conventional manner a foamablecomposition comprising:

(A) at least about 20 percent by weight based upon the total weight ofcomponents A, B and C of an amine initiated, highly branched polyetherpolyol having a hydroxyl group to molecular weight ratio of at least1:333,

(B) from about 0 to about 46 percent by weight when the combined weightof A and B is greater than about 86.5 percent but less than about 92percent and from about 0 to about 63 percent by weight when the combinedweight of A and B is greater than about 86.5 percent, said quantity of Bbeing based upon the total weights of components A, B and C of highlybranched hydroxyl initiated polyether polyol having a hydroxyl group tomolecular weight ratio of at least 1:333,

(C) from about 9 to about 50 and preferably from about 10 to about 33percent by weight based upon the combined weight of A, B and C of alightly branched polyether polyol having a hydroxyl group to molecularweight ratio of less than about 1:500,

(D) a polymethylene polyphenyl isocyanate having an averagefunctionality of from about 2 to about 3.2 and preferably from about 2.1to about 2.8,

(E) from about 0 to about 2.4 percent by weight based upon the combinedweight of components A, B and C of water,

(F) a volatile organic blowing agent,

(G) from about 0 to about 0.5 percent by weight based upon the combinedweight of A, B and C of a catalyst for urethane formation, and

(H) a silicone oil cell control agent;

wherein the isocyanate, component D, is employed in a quantity that willprovide an NCOzOI-I ratio of from about 0.5 :1 to about 0.9:1 andpreferably from about 0.6:1 to about 0.8:1.

The foams of the present invention may be prepared by mixing togetherthe previously described foamable composition and placing the resultantmixture into an Open 3,746,666 Patented July 17, 1973 container such asa box or other open vessel or moving troughs or conveyers wherein thecomposition is permitted to rise freely.

The water absorbable polyurethane foams of the present invention areuseful as floral foams, 'baflie foams and filter foams.

The floral foams are additionally characterized as possessing theability to absorb and retain at least about 60% by volume of Water(preferably at least about These foams are particularly useful in thefresh-cut flower industry in that they not only provide water necessaryto prolong the decorative life of the fresh cut flowers but may alsoserve as the frog i.e. the device employed to maintain the flowers in anarranged decorative position.

Those foams of the present invention which absorb and readily releasethe absorbed water are particularly useful as baffle or filter foams.The baflle foams would be particularly useful as an anti-sloshing mediain fuel tanks for aircraft and the like. The filter foams are useful asfilters for removing particulate matter from fluids, i.e. gaseous and/orliquid media.

The density of the foams may be varied in the usual manner by varyingthe quantity of blowing agent. The density variations are believed toaifect the cell size which would tend to vary the use of the foams infilter applications as to the size of particulate matter which could beremoved from the fluid employed. The particular speed with which liquidscan be filtered through the foam can be varied by the application ofpressure and vacuum means.

Suitable amine initiated, highly branched polyether polyols which may beemployed as component A of the foam compositions of the presentinvention include those reaction products of an amine having from about2 to about 5 active hydrogens as determined by the Zerewitinofi methodsuch as for example ammonia, ethylene diamine, aminoethylethanolamine, 2aminoethanolamine, N-methyldiethanolamine, diethylenetriamine,tris(hydroxymethyl)aminomethane, benzene sulfonamide, mixtures thereofand the like with a vicinal alkylene oxide or a halogenated derivativethereof having from about 2 to about 4 carbon atoms such as, forexample, ethylene oxide, propylene oxide, 1,2-butylene oxide,epichlorohydrin, mixtures thereof and the like and wherein the resultantproduct has a number of hydroxyl groups to molecular Weight ratio of atleast about 1:333.

Suitable hydroxyl initiated, highly branched polyether polyols which maybe employed as component B of the present invention include thosereaction products of a polyhydroxyl containing compound having fromabout 2 to about 8 hydroxyl groups, such as, for example, glycerine,sucrose, sorbitol, trimethylolpropane, mixtures thereof and the likewith a vicinal alkylene oxide and halogenated derivatives thereof,having from about 2 to about 4 carbon atoms such as, for example,ethylene oxide, propylene oxide, 1,2-butylene oxide, epichlorohydrin,mixtures thereof and the like, and wherein said product has a hydroxylgroup to molecular weight ratio of at least about 1:333.

Suitable lightly branched polyether polyols which may be employed ascomponent C include those prepared from the same compounds as thehydroxyl initiated highly branched polyether polyols except that theproducts have a hydroxyl group to molecular weight ratio of less thanabout 1:500.

Other suitable lightly branched polyether polyols include theester-modified polyether polyols described in a copending applicationSer. No. 67,233 by Robert W. McAda, Ir. having the title Ester-ModifiedPolyether Polyols filed on Aug. 26, 1970, now abandoned.

Suitable polymethylene polyphenylisocyanates which may be employedinclude, for example, those represented by the formula wherein n has avalue such that the average NCO func tionality is at least 2 andpreferably about 2.6.

The quantity of isocyanate employed is that which will provide an NCOzOHratio of from about 0.50:1 to about 0.9:1 and preferably from about0.60:1 to about 0.80:1.

Suitable cell control agents which may be employed include for example,the silicone oils, and the like.

These cell control agents may be employed in quantities of from about0.5 to about 2.0 percent by weight based upon the combined weight of A,B and C.

Suitable organic volatile blowing agents which may be employed include,for example, aliphatic hydrocarbons boiling below 110 C. and halogenatedaliphatic hydrocarbons boiling below 110 C. such as, for example,dich'lorodifluoromethane, trichlorofiuoromethane, methylene chloride,hexane, hexene, pentane, those suitable blowing or foaming agentsdisclosed in US. Pat. No. 3,072,582, mixtures thereof and the like.Those skilled in the art will recognize that the quantity of blowingagent will vary according to the density desired but is usually in therange of from about to about 50 percent by weight based on the combinedweight of A, B and C.

Other optional components which may be employed include inert fillerssuch as clays, talc, sodium carbonate, metal powders and the like,colorants such as pigments and/or dyes and the like, antioxidants,catalysts for urethane formation including tertiary amines such as, forexample, triethylenediamine, tctramethylenediamine,tetramethylquanidine, tetramethylbutane diamine, dimethyllead octoate,stannous octoate, dibutyltindilaurate, mixtures thereof and the like.

The following examples are illustrative of the present invention and arenot to be construed as to limiting the scope thereof in any manner.

EXAMPLES Vol. percent water pick-up weight of water absorbed 100-geometric volume of sample, in cm.

The percent loss by the dripping test was determined by immersing a 2 x2" x 2" sample for 3 minutes. The quantity of water pick-up isdetermined and the weight of water which leaks from the corner of thesample when held above a container during a period of one minute isdetermined.

Dripping tendency is then calculated by the following:

weight of water lossX 100 Percent weight of water absorbed The percentwater retained is calculated by the following equation:

Percent water retained-:percent water absorbed --(percent water absorbedXpercent Water loss) For Example 2 the percent water retained=90 ethanolamine, salts of tin and lead such as for example, (90 X .05 =904.5-=85.5.

Component and Comparaproperties Ex. 1 Ex. 2 Ex. 3 Ex. 4 tive Ex. A Ex. 5Ex. 6 Ex. 7 Ex. 8

A(polyol), grems/pbwJ- P1, 150/395 P1, 150/395 P1, 150/395 P1, 150/395P1, 150/395 P1, 284/71.5 P1, 160/40 P5, 155/395 P5, 155/395figlploglyog, grzitmslpbwn P2, 150/395 P2, 150/395 P2, 150/395 P2,150/395 P2, 150/395 None P4, 140/35 P2, 155/395 P2, 155/395 p w. o(A-i-B-l-O) 79 79 79 79 79 71.5 79 79 C(polyol, grams/pbw... P3, /21 P3,80/21 P3, 80/21 P3, 80/21 P3, 80/21 P3, 113/285 P3, 100/25 P3, 82.7/21P3, 82.7/21 D(isocyanate), grams.-. D1, 420 D1, 420 D1, 420 D1, 420 D1,420 D1, 400 D1, 407.3 D1, 407.3 D1, 407.3 E(water) grams/pbw None 5, 1.32.0, 0.5 8.0, 2.1 10, 2.6 None None 5, 1.3 None F(blowing agent),

ams F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1,160 Gi atalyst), gram None None None None None None None None NoneH(cell control agent ams H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 4H1, 4 NCQFOH ratio" 0.75:1 0.67:1 0.72:1 0.63:1 0.60:1 0.75:1 0.77:10.63:1 0.71:1 Dens1ty,lbs./ft. 1.88 1.48 1.60 1.30 1.2 2.0 1.62 1.45 1.8Compression yield strength, p.s.i 7.1 8.8 7.1 10.1 11.0 18 12.0 9.0 7.5Water pick-up (3 min.)

percent by vol 90 90 72 50 83 87 90 90 Dripping tendency,

percent loss 60 5 14.5 7 5 10 6 5 Water retained, percent- 36 85.5 77 6747.5 74.7 81.8 85.5 36 Suggested utility It B or F F1 F1 F1 None F1 F1F1 B or F Component and Compara- Compara- Compara- Comparapropertiestive Ex. B Ex. 9 Ex. 10 Ex. 11 Ex. 12 tive Ex. 0 Ex. 13 tive Ex. D tiveEx. E

A(po1yol), grams/pbWJ- P1, 163/46. 5 P1, 150/395 P1, 150/395 P1,ISO/37.5 P1, 150/735 P1, ISO/38.75 P1, 170/375 P1, 131/37 P1, 133.4/37.1B(polyo1), grams/pbw. P2, 163/465 P2, 150/395 P2, 150/395 P2, 150/375P2, 150/375 P2, 120/3875 P2, 170/375 P2, 192.5/54 P2, 184.6/51.411212341121386) 93 79 79 79 79 79 79 91 88.5 C(polyol), grams/pbw- P3,24.4/7 P3, 80/21 P6, 80/21 P7, /25 P8. 100/25 P3, 70/225 P3, /25 P3,32.4/9 P3, 41.1/11.5 D(isooyanate), grams--. D1, 450 D1, 420 D1, 420 D1,400 D1, 400 D1, 490 D1, 160 D1, 443.5 D1, 441 E(water) grams/pbw...-None None None None None None None None None F(blowing agent), F1, 160F1, 160 F1, 160 F1, F1, 150 F1, F1, 160 F1, 160 F1, 160

ams. G catalyst), grams None G1, 2 None None None None None None NoneH(cell control agent), H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 4 H1, 5H1, 5

grams. NCOzOH ratio 0.75:1 0.72:1 0.75 0.77 0.77 1.10 0.55 0.75 0.75Density, 1bs./ft. 1.50 1.9 1.8 2.0 2.0 1.9 1.97 1.9 2.0 Compressionyield 16 11.0 7.0 8.0 8.0 1.9 3.0 N.D. N.D.

strength, p.s.i. Water pick-up (3 min.) 18 90 90 90 90 55 90 10 15percent by vol. Dripping tendency, N.D. 6 60 38 40 10 45 N.D. N.D

percent less. Water retained, percent. N.D. 84.6 36 56 54 49.5 49.5 N.D.N.D. Suggested utility 2 None F1 13 or F B or F B or F None B or F NoneNone See footnotes at end of table.

TABLEContinued Component Compara- Compara- Comparaand properties tiveEx. F tive Ex. G tive Ex. H Ex. 14 Ex. 15 Ex. 16 Ex. 17 Ex. 18 Ex. 19

A (polyol), grams/ P1, l35/37.1 P1, 84/23 P1, 130/38 Pl, 136.2/37 P1,277/50 Pl, 258/60 P1, 85/23 P1, 150/38 Pl, 150/38 B (polyol), grams] P2,181.9/50 P2, 234/64 P2, 130/38 P2, 178.3/48.6 None None P2, 232/63 P2,150/38 P2, 150/38 A+B, pbwpf 87.1 87 76 85.6 50 86 76 76 C (polyol), grams/ P3, 46.8/12.9 P3, 48/13 P3, 80/24 P3, 52.6/14.4 P3, 227/50 P3,172/40 P3, 51/14 P3, 80/24 P3, 80/24 D (isocyanate), grams... D1, 463.3D1, 434 D1, 460 D1, 433 D1, 345 D1, 370 D1, 432 D2, 420 D1, 420

E (water) grams/pbw-.. None None None None None None None None None F(blowing agent), F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1, 160 F1, 160F1, 160 F1, 160

grams.

G (catalyst), grams None G1,1 None None None None G1, 1 None None H(cell control agent), H1, H1, 4 H1, 4 H1, 5 H1, 4 H1, 4 H1, 4 H1, 5 H2,4

grams.

NCO:OH ratio 0.75 0.75 0.96 0.75 0.75 0.75 0.75 0.75 0.67

Density, lbs/ft. 2.0 1.75 2.0 1.9 1.9 1.9 1.75 1.9 1.78

Compression yield N.D. N.D N.D. 5 1 3 7 8.0 8.7

strength, p.s.i.

Water pick-up (3 min.) 53 55 47 88 90 90 88 90 85 percent by vol.

Dripping tendency, N.D. N.D. N.D. 60 18 10 3 percent loss.

Water retained, percent N.D. N.D. N.D. 79.2 46 63 72.2 81 82.5

Suggested utility 2 None None None Fl B or F F1 F1 F1 F1 1 Percent byweight based upon the combined weights of A, B, and C.

am. 8 Ex. 1 foam had an air flow volume of 5.0 ftfi/min. as determinedby ASTMD156469. Nora-Polyol P1 is an amine initiated polyether polyolthat is the reaction product of about 3 moles of propylene oxide withamlnoethylethanolamine having a molecular weight of about 280 and etherpolyol that is the reaction product of glycerine with ethylene oxide haPolyol P3 is the reaction product of glycerine an Varanol CP-470l havinga molecular weight of about 4700 and a hydroxyl group to molecularweight ratio of about 1: 1565; product of glycerine with propylene oxidehaving a hydroxyl group to molecular weight ratio of about 1:86;

weight ratio of about 1:74;

a hydroxyl group to molecular weight ratio oi about 1:70;

ving a molecular weight of about 225 and a hydroxyl group to molecularPolyol P2 is a hydroxyl initiated polyd propylene oxide end-capped withethylene oxide sold commerically as Polyol P4 is the reaction Polyol P5is the reaction product of diethylene triamine with propylene oxide at amolar ratio of about 1 to 5 respectively and having a hydroxyl group tomolecular weight ratio of about 1:79; a hydroxyl group to molecularweight ratio of about 1:1635. about 1:2000; Polyol P8 is apolyoxypropylene lenc polyphenylisocyanate having an NC Blowing Agent F1is CFClaZ H2 is a silicone oil, SF-l066 sold commercially by GeneralElectric;

according to the following procedure.

All of the components except the isocyanate were mixed, then theisocyanate was added and the mixture stirred vigorously for 10 secondsand poured into a 16- ounce glass bottle. The foam was trimmed flushwith the top of the bottle. The foam Was wetted with 250 ml. of gasolinewhich was subsequently removed by allowing the gasoline to drip untilthe dripping stopped. Then 185 grams of gasoline was poured into thebottle which was then inverted and the gasoline was collected for aperiod of 1 minute during which time 172 grams was recovered whichrepresented a recovery of 93% of the gasoline added.

A foam of the same composition as above had the following propertiesNCOzOH ratio=0.75

Density: 1.88 lbs./ft.

Compressive yield strength=7.1 p.s.i. Water pick-up=90% Drippingtendency=60% Water retained=36 Suggested utility=baffie or filter foamWe claim:

1. A polyurethane foam composition which absorbs at least about 70percent by volume of water, said foam re sulting from subjecting tofoaming conditions a composition comprising:

(A) at least about 20 percent by weight based upon the combined weightof A, B, and C of an amine Polyol P6 is the reaction product of P3 withabout 3 moles of maleic anlydride and Polyol P7 is a polyoxypropyleneglycol having a hydroxyl to molecular weight ratio of glycol having ahydroxyl to molecular weight ratio of about 1:1000; 0 equivalent weightof about 134 and an average functionality of about 2.8;polyphenylisoxyanate having an NCO equivalent weight of about 131 and anaverage functionality of about 2.3;

Cell Control Agent H1 is a silicone oil, DCXF1l546 sold commercially byDow Corning Corp.;

N .D.=Not determined.

about 6 moles of ethylene oxide the resultant product having IsocyanateD1 is a polymethy- Isocyanate D2 is a polymethylene Catalyst G1 isdimethylethanolamine Cell Control Agent initiated polyether polyolhaving a hydroxyl group to molecular weight ratio of at least about1:333,

(B) from about 0 to about 46 percent by weight when the combined weightof A and B is greater than about 86.5 but less than about 92 percent andfrom about 0 to about 63 percent by weight when the combined weight of Aand B is greater than about 20 percent but less than about 86.5 percentby weight based upon the combined weight of A, B, and C of a hydroxylinitiated polyether polyol having a hydroxyl group to molecular weightratio of at least 1:333,

(C) from about 9 to about 50 percent by weight based upon the combinedweight of A, B, and C of a hydroxyl initiated polyether polyol having ahydroxyl group to molecular weight ratio of less than about 1:500,

(D) a polymethylene polyphenylisocyanate having a functionality of fromat least about 2 to about 3.2,

(E) from about 0 to about 2.4 percent by weight of the combined weightsof A, B, and C of Water,

(F) a volatile organic blowing agent,

(G) from about 0 to about 0.5 percent by weight based upon the combinedweight of A, B and C of a catalyst for urethane formation, and

(H) a silicone oil cell control agent, wherein the isocyanate, componentD, is employed in a quantity that will provide an NCOzOH ratio of fromabout 0.5 :1 to about 0.9: 1.

2. The composition of claim 1 wherein component C is employed in aquantity of from about 10 to about 33 percent and the NCOzOH ratio isfrom about 0.621 to about 0.8 l.

3. The composition of claim 2 wherein the amine initiated polyetherpolyol, component A, is the reaction product of propylene oxide withaminoethylethanolamine or diethylenetriamine.

4. The composition of claim 2 wherein the polyether polyol, component B,is the reaction product of glycerine with ethylene oxide.

(References on following page) 7 8 References Cited 924,111 4/1963 GreatBritain 260-25 Grat Brltaln 3,457,203 7/1969 Cohen et al 260-25 DONALDCZAJA, primary Examiner 2,977,330 3 1961 B 260 .5 3 471 4 6 5 C.ASSlStallt Exammer FOREIGN PATENTS US. Cl. X.R.

254,818 2/1961 Australia 260-25 Q 19 seems PATENT 01mm CERTIFFCATE 9FC(PRRECTION Patent No. 3,746,666 pm July 17 1973 Inventor) Gerald WavneNeal and Llewellvn Delphin Booth It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

1''" I '1 Colu 4, line 40,, place a minus sign before 90 X .05)".

In the Table at Col. 3 and 4, opposite A (polyol) in Ex. 12,

change 73.5" to --37 .5-.

In the Table'at Col. 3 and 4 opposite A (polyol) in Comparative Ex. C,change "150'5 to --l20-- In the Table at Col. 3 and 4 opposite C(polyol) in Ex. 12,

change "P8." to --P8,-- 1

In the Table at Col. 5 and 6 opposite E (water) in Ex. 19,

change "none" to -5,

Inthe footnote to the Table at Col. 5 and 6, change the first word inthe third 'line from "the bottom from "polyphenylisoxyanate" to--polyphenylisocyanate--n Signed and sealed this 12th day of November1974.

(SEAL) Attest: MCCOY M. GIBSON JR. 0. MARSHALL DANN Arresting OfficerCommissioner of Patents

